EXTRUSION MOLD AND METHOD OF USE

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to U.S. Patent Application

No. 1 1 /648,129, filed on December 28, 2006, the disclosure of which is

incorporated by reference herein in its entirety, including drawings.

FIELD OF THE INVENTION

[0002] The present invention relates generally to systems and methods

for creating extruded products while venting steam and/or gases during the

extrusion process.

BACKGROUND OF THE INVENTION

[0003] The pressure to use biodegradable disposable packaging has

been steadily increasing in the last decade. As recently as March, 2003,

Taiwan has outlawed the use of Styrofoam in disposable packaging. Even

China's major cities such as Beijing and Shanghai have outlawed the use of

Styrofoam materials in disposable packaging. Various attempts have been

made in the prior art to manufacture starch based disposables for use in food

service items such as trays, plates, and bowls. Some methods include

producing starch based packaging that has materials vented in excess of the

final product as can be evidenced when one inspects the finished product.

However, these technologies use male and female molds and not extrusion

dies. Attempts to extrude starch do not include venting during the extrusion

process, and instead include injection gases in an attempt to foam the starch.

[0004] Further, the majority of the existing extrusion processes using

starch are geared towards producing thick sheeted materials that are then

bonded together to form packaging materials that replace thick Styrofoam.

Examples are protective packaging for shipping television sets or other similar

electronic or heavy systems. Unfortunately, existing efforts have not been

successful for producing articles such as toilet paper rolls, chop sticks, or

straws primarily due to the inability to reduce pressures during the baking-

extrusion process.

[0005] Accordingly, there is a need for improved systems and methods

for extruding materials while continually venting gases during the extrusion

process without any substantial material losses.

SUMMARY OF THE INVENTION

[0006] In one embodiment of the present invention a method of extruding

a materal is provided comprising the steps of providing an extrusion head

having a plurality of venting gaps for venting a gas; providing an extrusion

mixture comprising fibers and water to the extrusion head; extruding the

mixture through the extrusion head wherein the step of extruding comprises

heating the mixture within the extrusion head such that the gas is release from

the mixture; venting the gas from the extrusion head through the plurality of

venting gaps such that the remaining mixture is substantially retained by the

extrusion head.

[0007] In another embodiment, an extrusion head is provided comprising

a plurality of venting gaps, wherein the venting gaps are dimensioned to allow

for the venting of a gas but substantial retention of the remaining material to

be extruded during extrusion and wherein the venting gaps are both radial and

axial and the extrusion head is multi-piece.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to fully understand the manner in which the above-recited

details and other advantages and objects of the invention are obtained, a

more detailed description of the invention will be rendered by reference to

specific embodiments thereof which are illustrated in the included drawings.

Understanding that these drawings depict only typical embodiments of the

invention and are not therefore to be considered as limiting of its scope, the

invention will be described and explained with additional specifity and detail

through the use of accompanying drawing in which:

[0009] Figure 1 is a view of a basic venting feature of an embodiment of

the present invention.

[0010] Figure 2 is a view of a cross section of an extruder head of an

embodiment of the present invention.

[0011] Figure 3 is a perspective view of a venting feature applied in an

axial and trans-axial fashion to the extruder head of an embodiment of the

present invention.

[0012] Figure 4 is a cross section view of an extruder head of an

embodiment of the present invention with a venting features with a center

mandrel used to allow the formation of tube shapes.

[0013] Figure 5 is a perspective view of an extruder head of an

embodiment of the present invention showing a mix with or without fibers

going through the extruder and exiting formed on the other end.

[0014] Figure 6 is a perspective view of an extruder head of an

embodiment of the present invention showing continuous fibers and mix being

introduced to the extruder and exiting formed on the other end..

[0015] Figure 7 is a cross section view of a formed product of an

embodiment of the present invention with continuous fibers in a relatively

straight configuration in a tube and rod configuration.

[0016] Figure 8 is a perspective view of the extruder of an embodiment

of the present invention being fed fibers that are braided or knitted then

introduced into the opening along with the starch mixture.

[0017] Figure 9 is a perspective exploded view of the various pieces of

an embodiment of the present invention that are designed in such a way as

they fit into an outer sleeve that would hold them together but still allow

venting of the steam or gases.

DETAILED DESCRIPTION

[0018] The following description of the invention is intended to illustrate

various embodiments of the invention. As such, the specific modifications

discussed are not to be construed as limitations on the scope of the invention.

It will be apparent to one skilled in the art that various equivalents, changes,

and modifications may be made without departing from the scope of the

invention, and it is understood that such equivalent embodiments are to be

included herein.

[0019] In an embodiment of the present invention, the characteristics of

baked goods are used to provide high efficiency systems and methods for

extruding starch-based articles as well as similar behavior materials. The

systems and methods of the present embodiment accomplish the ability to

extrude thin and thick walled extrusions that could not previously be produced

due to the inability to vent gases during the extrusion process.

[0020] In the present embodiment, vents may be added within an

extrusion tunnel, axially and/or through a cross section. Thus, referring to

Figures 1 -3, one embodiment of the inventive systems comprises a multi-

piece extrusion head 10. The extrusion head 10 comprises one or more axial

venting gaps 20 and/or radial venting gaps 30 that extend along the mating

perimeter of the different pieces of the extrusion head 10. The size of the

venting gaps 20, 30 can be constant or vary and are preferably from between

about 0.001 " to about 0.006" to allow steam and/or other gases to escape

during the extrusion process, but contain the material to be extruded. The

extrusion head 10 may also comprise venting gaps 20, 30 along the axis of

the extrusion as well as radially between multiple pieces that are then

attached together or may comprise only axial venting gaps 20 or only radial

venting gaps 30.

[0021] In one aspect of the present embodiment the composition to be

extruded can be water, alcohol or other liquid based. The composition may or

may not contain additives such as fibers to improve the properties of the

composition.

[0022] According to another embodiment of the invention, during the

extrusion process, fibers can be chopped up and mixed in an extrusion

mixture or fibers can be continuous and pulled through as is performed in

composite pulltrusions. For pulltrusions, the fibers are pulled through a

material flow opening of the extruder and are baked directly into the starch

mixture. This can form a very axially strong product since the fibers are

continuous.

[0023] According to another embodiment of the invention, the fibers can

be knitted together to form different shapes that are then pulled through the

extruder and baked into the starch. This method allows for biaxially strong

extrusions. It also allows the user to customize required strength solutions by

producing a fiber matrix that is then baked into the starch matrix.

[0024] According to another embodiment of the invention, the addition of

a center mandrel with or without venting features on this mandrel and heated

or unheated which would allow for the formation of tubes such as paper roll

centers, toilet paper centers, and straws.

[0025] One feature of some embodiments of the invention is that the

number of venting gaps can be customized, i.e., increased or reduced in

numbers or size, to better control the steam and gas release process. It is

important to note that not only round shapes but squares, rectangles,

octagonal, namely, any cross-section that can be extruded, could be

developed for this process. As previously mentioned, the addition of center

mandrels could help in forming tube like sections instead of purely solid

shapes.

[0026] Methods according to some embodiments of the invention

generally comprise the steps of mixing at least water and starch together to

form a starch-based composition then extruding the composition through the

special die heads. The heat starts to bake the starch which in turn forms a

skin wherever it comes into contact with the heated extruder surfaces. In

addition, the heat turns the water in the composition to steam which is allowed

to escape via the venting features. The mixture can have premixed fibers in it

or continuous fibers that can also be stitched together or weaved in a shape to

improve the overall strength of the finished product.

[0027] These and other features of embodiments of the present

invention will become more fully apparent from the following description and

appended claims, or may be learned by the practice of the invention as set

forth hereinafter.

[0028] In another embodiment of the present invention mold systems

and methods of use are provided such that aqueous starch-based

compositions and baked goods articles that use the conversion of water to

steam may be produced using an extruder that allows the venting of such

gases and/or steam. The extruder is vented in such a way as to allow steam

to escape, but retain the composition until the exit end.

[0029] More particularly, some embodiments use the physical property of

starch and other baked goods to allow the release of steam without releasing

the composition. When the mixture first contacts the heated surfaces of the

extruder, they form a skin and the water in the mixture starts to turn to steam.

This method of allowing the venting of the steam at multiple areas along the

extrusion path allows for more dense products that can withstand much higher

forces. By adding steam release gaps using the several different methods

describes herein, the baking time can be reduced thus increasing output.

[0030] By methods of the present embodiment one may produce tube

and other extruded shapes that would be cheaper than existing paper and

plastic products. Moreover, the overall process tends to be relatively benign

and does not use the harsh chemicals normally associated with paper or

plastic products.

[0031] In another embodiment of the present invention, the above

extrusion concept may be applied to any material that can be placed in a

cavity which when exposed to the heated surface produces a skin that is

semi-permeable to the liquid being turned to gas and is not limited to aqueous

based mixtures. Moreover, the mixtures can be edible or non-edible and

could include various components for modifying the properties of the mixture,

such as the addition of scents or other materials.

[0032] Referring to Figure 4, a cross-section of an extruder head having

venting gaps 100 and an inner mandrel 1 10 that would be used for tube

structure manufacturing is shown.

[0033] Referring to Figure 5, a trimetric view showing the extrusion of a

tube structure 200 through an extruder head 210 from mix 220 with fiber 230.

[0034] Referring to Figure 6, a trimetric view showing a mix 300 and

continuous fibers 310 being introduced to the extruder head 320 to produce

an extrusion 330. Referring to Figure 7a, a cross section of the extrusion 330

is shown demonstrating fiber 310 orientations for a tube extrusion, and

referring to Figure 7b, a cross section of the extrusion 330 is shown

demonstrating fiber 310 orientations for a rod configuration. As can been

seen in Figures 7a and 7b, the fiber 310 is oriented along the length of the

tube or rod.

[0035] Referring to Figure 8, a continuous fiber 400 being knitted into a

general cohesive shape 410 is shown being inserted into a mix 420 which is

then extruded through the extruder head 430 to form the extrusion 440.

[0036] Referring to Figure 9, a trimetric view of an extruder head 500

that may be inserted into a pipe 510 or similar to hold the individual pieces of

the extruder head together is shown.

[0037] As stated above, the foregoing is merely intended to illustrate

various embodiments of the present invention. The specific modifications

discussed above are not to be construed as limitations on the scope of the

invention. It will be apparent to one skilled in the art that various equivalents,

changes, and modifications may be made without departing from the scope of

the invention, and it is understood that such equivalent embodiments are to be

included herein. All references cited herein are incorporated by reference as if

fully set forth herein.